1. Field of the Invention
This invention relates to the germination of resting spores and more particularly to methods for increasing significantly the number or percentage of resting spores that are germinated.
2. Description of the Prior Art
Entomophthora species are known to cause large scale epizootics and produce resting spores which might be stored for long periods. Consequently, these fungi are excellent candidates for biological control. However, the practical utilization of Entomophthora species as biological control agents has been hampered by the inability to produce large quantities of resting spores and induce their germination. Production of resting spores in artificial media and germination of the produced spores have been the problems.
In the past, many workers such as the following have attempted to germinate or increase the germination of resting spores; Nowakowski, Pamiet. Acad. Umiejejnosci zu Krakau 8, 153-183, 1884; Dustan, Proc. Acad. Entomol. Soc., 9, 14-36, 1924; Gilliatt, Proc. Acad. Entomol. Soc., 10, 46-54, 1925; Schweizer, Planta 35, 132-176, 1947; Hall and Halfhill, Jour. Econ. Entomol., 52, 30-35, 1959; and Krejzova, Jour. Invert. Pathol. 12, 460, 1968 and Ceska Mykol 25, 231-238, 1971. Although Hall and Halfhill reported one experiment in which 15% germination was obtained the level of germination obtained by the above workers was generally less than 5%. French and Gallimore (Agr. Food Chem 19, 912-915, 1971) reported on the effect of a number of chemical compounds on uredospore germination of wheat stem rust and found some of them to have a stimulatory effect. Ethanol, because it was found to be inactive and without any stimulatory effect on germination, was used to solubilize some of the nonwater-soluble, volatile, oily compounds. French and Weintraub (Arch. Biochem. and Biophys., 72, 235- 237, 1957) has previously reported that extracts of uredospores of wheat stem rust contained substances capable of inducing germination of the dormant spores. They also found that the extracts contained at least two active compounds, one of which was pelargaraldehyde (n-nonanal) and showed that this compound stimulated germination of wheat rust spores to some extent. However, none of the prior art discloses any means of germinating resting spores that approaches the 100% level. Furthermore, none of the known procedures discloses a method or substance that is easily adaptable to large scale commercial size production and germination of resting spores.